This invention relates to methods of utilizing recovered drywall, and in particular, to the use of recovered drywall to reduce insect population in animal habitats, such as dairy barns, and to reduce microbial, e.g., bacterial population in such structures and particularly on animal surfaces, as well as to reduce animal habitat odor.
It has been estimated that 12-27% of construction and demolition debris is waste drywall. For single family construction, it is estimated that there is about 1-1.5 lbs. of drywall waste per square foot of floor area, e.g., construction of a 2000 sq. ft. may yield up to 3000 lbs. of waste or scrap wallboard. As such, waste drywall is the second largest source of waste, second only to wood. As with most waste or scrap, the community landfills are the ultimate resting place for waste drywall; some landfills, however, have already banned landfilling of gypsum drywall.
The terms "drywall", "wallboard", "sheetrock", "building board", "plasterboard" or "gypsum board" as used herein and generally in the industry, refer to a prefabricated substantially rectangular walling material which is of sandwich construction, i.e., a hardened gypsum-based plaster core or slab sandwiched between fibrous material, e.g., paper, facings or cover sheets. Gypsum is the most common of the naturally occurring sulfate minerals, and a calcium sulfate hydrate (i.e., 79% calcium sulfate and 21% water), CaSO.sub.4 H.sub.2 O. The composition of a typical gypsum-based wallboard is about 75-95% gypsum, 3-9% paper, 1% fiberglass, 0.3-1% starch and the remainder, a combination of organic binders, adhesives, dispersants, and water resistant additives. It is noted that unfaced gypsum board is also known; see, e.g., U.S. Pat. No. 5,171,366 issued to Richards et al.
Recently, various methods of processing the waste or scrap drywall to separate the gypsum-based core and the backing paper are known. See, e.g., U.S. Pat. No. 5,100,063 issued to Bauer; U.S. Pat. No. 5,183,213 and 5,238,195 issued to Knez; U.S. Pat. No. 5,433,388 issued to Hirz et al.
The recovered gypsum-based core has been used to re-manufacture drywall. However, some agricultural uses have been reported. Most of these uses of the recovered core material parallel the uses of virgin gypsum, e.g., soil amendment to neutralize alkaline and saline soils, to improve the permeability of argillaceous materials, to provide sulfur and calcium for plants, to remediate soils high in sodium and to reduce soil crusting.
As with all waste materials, there is a need for finding other uses for the recovered product. The need for such uses is no greater than in the drywall area considering the large amounts of waste wallboard created each year.